Charged particle's elliptic flow in 2+1D viscous hydrodynamics at LHC ($\sqrt{s}$= 2.76 TeV) energy in Pb+Pb collision

TL;DR

This study uses 2+1D viscous hydrodynamics to analyze elliptic flow in Pb+Pb collisions at 2.76 TeV, revealing that viscosity is essential to match elliptic flow data, with an estimated viscosity to entropy ratio of 0.06.

Contribution

First simultaneous analysis of multiplicity, spectra, and elliptic flow data at LHC energies using viscous hydrodynamics to extract the QGP viscosity.

Findings

Viscosity is necessary to explain elliptic flow data.

Estimated shear viscosity to entropy ratio is approximately 0.06.

Multiplicity and spectra data do not require viscosity.

Abstract

In the Israel-Stewart's theory of second order hydrodynamics, we have simulated $\sqrt{s}$=2.76 TeV Pb+Pb collisions. ALICE data for the centrality dependence of charged particles multiplicity, $p_T$ spectra in 0-5% collisions, centrality dependence of integrated and differential elliptic flow are analysed. Analysis indicate that while ALICE data on charged particles multiplicity or $p_T$ spectra do not demand any viscosity, viscosity is demanded by the elliptic flow data. From a simulataneous fit to all the data sets, viscosity to entropy ratio in $\sqrt{s}_{NN}$=2.76 TeV Pb+Pb collisions is extracted as, $\eta/s=0.06\pm 0.02$.